a) Field of the Invention
The invention is directed to a process for the automated ejection of screws using pull-out mechanisms or ejector mechanisms which are known per se set forth in the preamble of claim 1 and to a device for carrying out the process. The invention is directed in particular to the automated ejection of screws used in screw presses or screw-type extruders for producing dough and pasta products, these screw extruders being connectable with swivelable mixing kneaders.
b) Description of the Related Art
It is generally common practice to remove pressing screws and conveying or feed screws from the cylinder of a screw extruder for cleaning purposes or for replacing worn screws. Spindle-operated pull-off or ejecting devices and hydraulically actuated pull-off or pull-out devices with one or two cylinders are known for this purpose. For example, DE-AS-1268367 describes a device for ejecting the screw from the cylinder of a screw-type extruder. A pressure rod is connected with the hydraulic piston of a screw adjusting device by means of a mechanical coupling. The coupling carries the pressure rod along only in the screw ejecting direction. In addition, the pressure rod is provided with drivers whose distance from one another corresponds to the piston stroke. A plurality of strokes are required to eject the screw from the cylinder. This device is mechanically costly and occupies a large amount of space. The free cantilevering or protruding length which increases with the number of strokes is not supported, which can lead to tilting and can result in damage to the screw.
European Patent Application No. 271399 describes a process and apparatus for assembling and disassembling extruder screws. The extruder screws are transported and supported in a fixed or stationary manner. However, handling by use of load suspension means and stop means is very cumbersome.
It is also known to provide screw shafts with axial bore holes for tempering (DD-PS 200079). However, such screw shafts are not suitable when higher pressures are applied.